Ministers hope to reduce re-offending rates by improving inmates' education
Schemes to improve prisoners' basic skills and qualifications in English jails have "failed in almost every respect", an MPs' committee has said.
They were of "little practical use" to those serving less than a year and those moving between prisons could find themselves unable to continue.
Only 20% of those who needed help the most had joined a course, MPs said.
But ministers said there had been "significant progress" and the service was "far from failing".
In its report the Commons public accounts committee said helping prisoners improve basic and vocations skills was a major plank of the government's policy to cut reoffending.
Many prisoners had "severe" learning problems, nearly 40% had a reading age below that expected of an 11-year-old and half of people in custody had no qualifications, they said.
Since 2006, the Offenders' Learning and Skills Service (OLASS) has handled inmates' education provision in England.
But the committee said only about a fifth of those with "serious literacy or numeracy needs" enrol on a course that would help them and more could be done to motivate them.
It notes there are challenges as many prisoners have mental health, alcohol or drugs problems and the "operational requirements" of prisons had to take priority over learning.
But it says there appeared to be "confusion" over how funding should be prioritised, "tensions" over objectives and a risk that "performance incentives" for those providing the service did not encourage them to reach out to the hardest-to-reach prisoners.
"Payments are made to providers irrespective of offender take-up, attendance or achievement," the report said.
"The programmes currently on offer are likely to be of limited practical use to prisoners serving less than 12 months, and reconviction rates for these prisoners are not improving."
'Far from failing'
It also raised concerns about a lack of assessment of some prisoners, "frequently deficient" learning plans and the lack of a core curriculum, which meant if inmates moved prisons they could find it hard to continue their courses.
The committee's Conservative chairman, Edward Leigh, told the BBC: "The people who are responsible are those who actually run our prisons, they seem to want to have above all a quiet life, they want to have tame prisoners who are locked up.
He added: "I think you want to have a vigorous really committed service which believes in the power of resurrection of these people and says 'I'm going to give these people a life skill'."
In a statement with the report, he added: "OLASS was set up to overcome long-standing problems in the delivery of skills and learning for offenders. In practice, it has failed in almost every respect."
But the government said the report had been based on a National Audit Office study which focused on "very early days" in the service, since when significant changes and a "marked improvement" had been made.
In a joint statement, further education minister Sion Simon and minister for offender management David Hanson MP said the service was "far from failing".
They said nearly 40% of inmates had taken part in training courses in 2007/8, compared with less than 30% when the service before 2006.
"OLASS has made significant progress since its creation with a solid growth in the number of offenders learning new skills," they said.
"All the agencies involved in offender learning will continue to work together and are wholly focused on reducing reoffending through skills and employment."